The year 1993 was a huge turning point in Ranjith's career. Devasuram, his film based on the life of Mullassery Rajagopal,[4] a fatherlike figure to him, turned into a huge hit at the box office. With Mohanlal in the lead and directed by I. V. Sasi, Devasuram was both critically and commercially a very big success. Mohanlal's performance was highly appreciated and it opened a new genre of feudal stories in Malayalam cinema. Within two months of the release of Devasuram, his next movie, Maya Mayuram (directed by Sibi Malayil and starring Mohanlal) was released, but it did not meet its anticipated success. According to Ranjith, Maya Mayuram is one of his best films and its failure affected him greatly. Ranjith mentioned in an interview that when several directors, whom he approached with the script, showed no interest in Maya Mayuram, it was Mohanlal who convinced Sibi Malayil to take it up. Yadavam, his next film in 1993 (directed by Jomon and starring Suresh Gopi) did him no good in career. In the year 1994, Ranjith joined hands with Shaji Kailas for Rudraksham, again starring Suresh Gopi, who was at the peak of his career. This film generated significant hype in the market as Shaji Kailas- Suresh Gopi was a hot selling team at the time. But the loose script and clichéd punchless dialogues led to Rudraksham becoming a flop. His next piece of work, Rajaputhran, directed by Shajun Karyal, again with Suresh Gopi in the lead, became only an average grosser.[5] In the year 1997, he teamed again with Shaji Kailas for Asuravamsham, starring Manoj K Jayan and Biju Menon. This film yielded an average commercial response. But he was just biding his time. Towards the end of 1997, Ranjith penned Aaraam Thampuran, one of the blockbuster hits of his career. Directed by Shaji Kailas, this film broke several collection records and went on to become a financially and critically acclaimed hit. This film was also a turning point in the career of Mohanlal. With this film, Ranjith gained a reputation as a commercially viable scriptwriter. Then came Kaikudanna Nilavu, in 1998, directed by Kamal, starring Jayaram, yet another average grosser. In 1998 Ranjith scripted Summer in Bethlehem, directed by Sibi Malayil, starring Suresh Gopi and Jayaram, a super hit.[6] In 1999, Ranjith and Shaji Kailas produced the film Ustaad, directed by Sibi Malayil, starring Mohanlal. This film, written by Ranjith was a super hit at the box office.[7]

The year 2000 began with the release of Narasimham, directed by Shaji Kailas. With Mohanlal playing the lead role, this film became one of the biggest hits ever in the history of Malayalam cinema till then.[8][9] Yet again in 2000, together with Shaji Kailas, Ranjith repeated history. His Onam release Valliettan starring Mammooty was a commercial success. (Last script for Shaji Kailas).[10] With this film, Ranjith became the most successful scriptwriter of the time.

In 2001, Ranjith made his directorial debut with Ravanaprabhu, the sequel to Devasuram.[11] With Mohanlal appearing in dual roles as father and son, this film turned out to be another blockbuster.[12] In the year 2002, Ranjith came back with another blockbuster, Nandanam, starring Navya Nair and a new face, Prithviraj Sukumaran.[13] Ranjith produced this film along with his friend and actor Siddique. Nandanam, revolving around an innocent girl, her love for Lord Sri Krishna and her lover boy, was an entirely different and unexpected theme from Ranjith at that time. Despite the film having no big stars, fights or punch dialogues the film and that it was shelved after some pre-production activities, it became a hit.[14] In the year 2003, Ranjith directed Mizhi Randilum starring Dileep and Kavya Madhavan, another family drama, which failed to impress the masses, but was critically acclaimed. In the same year Ranjith scripted Ammakilikood, directed by Padmakumar, with Prithviraj in the lead, which also got the cold shoulder from the public. In 2004, Ranjith teamed up with Mammooty for Black, which was a complete commercial entertainer targeting the fans of Mammootty, but became a success at box office.[15][16] Then came Chandrolsavam, starring Mohanlal in 2005. The film was panned by the critics for its lack of content and it failed to endear to even the fans of Mohanlal.[17] However, Ranjith believes that it was not a bad film. He says, "Mohanlal fans expected too much. I don't think it was a bad film. Many who watched it on DVD called to say they were surprised it did not do well. Fans come in with pre-conceived notions on how the actor will be in the movie and the kind of story it will be, hence they could not grasp the poetic element in the film."[18] In 2006, he scripted and directed Prajapathi, starring Mammootty, was also blasted by critics,[19] and was another disastrous movie.[20] His next venture was an offbeat film Kaiyoppu. Though a flop at the box office, Kaiyoppu brought critical appreciation from far corners and that compelled Ranjith to work with plots and themes without any commercial ingredients. Notably, its lead actor Mammootty, took no payments to act in the film as the script impressed him so much.[21]

Renjith in Sharjah Book Fair-2012

In 2007, he regained commercial success by teaming up with director Joshiy for the first time for the big budget film Nasrani starring Mammootty, which became a superhit at the box office.[22][23][24][25] Ranjith's next venture, Rock & Roll, starring Mohanlal, was unable to attract critics and was a massive flop.[26][27] In the year 2008, Ranjith again stunned Kerala with his film Thirakkatha, based on actress Srividya's life,[28] which won the National Award for the Best Malayalam Feature Film. Starring Anoop Menon and Priyamani in the lead, the movie featured Prithviraj and Samvrutha Sunil in important supporting roles. The movie was able to bring out the best in the actors.[29] The movie did well at the box office as well and garnered many awards.[30] In 2009, Ranjith directed and wrote the script for Paleri Manikyam: Oru Pathira Kolapathakathinte Katha, which was widely acclaimed critically.[31]Mammootty's performance was widely appreciated in this film. Ranjith also introduced about thirty Malayalam stage artists through this film.[32] In the same year he came up with another unique creation, Kerala Cafe — a fusion of ten different short films by ten directors. Ranjith helmed this venture, which proved to be an experimental breakthrough in the Malayalam film industry. The different segments in the movie were conceived and connected based on the concept of Yatra or journey.[33]

In the year 2010, Ranjith wrote the story for the film Penpattanam, directed by V. M. Vinu. He then scripted and directed, Pranchiyettan and the Saint, starring Mammootty, was also widely accepted by movie buffs and the common people of Kerala,an excellent movie. It became the most popular film of the year and was also a commercial success. He is also occupied in the respected position of School Director for Cochin Media School, first authentic Film & Broadcasting Institute in Kerala.[34] Ranjith also appeared as judge in "Mammootty the Best Actor Award – II", an acting talent hunt reality show aired in Asianet.[35] In 2011 Ranjith scripted and directed a critically acclaimed satirical film Indian Rupee starring Prithviraj which was well received by the critics and was a commercial success. His next film, Spirit, primarily focused on the increasing habits of alcoholism in Kerala. Starring Mohanlal in the lead role, the film was critically acclaimed and was a box office success. He then produced and scripted for G. S. Vijayan's Mammootty starrer Bavuttiyude Namathil in 2012 which was a hit at the box office. His next film with Mammootty, Kadal Kadannoru Mathukkutty, in 2013 became profitable, but underperformed at the box office. Njaan, based on the novel ‘K T N Kottoor: Ezhuthum Jeevithavum’ by T P Rajeevan and featuring Dulquer Salmaan in the lead role, released on 19 September 2014.[36]